Radio resources for use in wireless communications are generally expensive and thus need to be used in a more efficient manner. On the other hand, conventional wireless communication systems often do not fully utilize the entire frequency bandwidth allocated to the systems. For example, both ends of an allocated bandwidth may be assigned as guard bands which are used not for data communication but for preventing interference between adjacent channels. Such interference may be caused due to various characteristics of wireless communication components. For example, a low-pass filter used in baseband signal processing may not completely block signal/power leakage out of an occupied bandwidth due to its general circuit characteristics. The guard bands may be reduced if it is possible to extend an occupied bandwidth to match the allocated bandwidth by enhancing the features of various components such as filters or amplifiers. Additionally, to fully utilize the allocated bandwidth, there is a need for eliminating interference between adjacent channels which is caused by the Doppler effect as a transmitter device or a receiver device moves relative to each other.